P

Parallel Light : A light that casts rays that are perfectly parallel to one another.
Pitch : The rotation of an object. Usually forward and back.
Pixels : (Basic image elements) The individual dots that are used to display an image on a computer monitor. Image size and resolution are defined in terms of number of pixels.
Pixel Depth : The number of bits used to generate a color at each pixel. For instance a pixel depth equal to one means that only black and white colors could be displayed; with a pixel depth equal to four, sixteen different colors could be displayed.
Plug-in Module : Third-party software that is loaded into the PhotoShop Plug-ins folder which enables it to be accessed from a PhotoShop menu. Or, a plug-in module that comes with PhotoShop that is used to facilitate Import, Export, file format conversion, or other operations.
PNG : Portable Network Graphics. A web based format that supports one alpha channel and transparency.
Point : A unit of measure that is used to describe type size (measured from ascender to descender), leading (measured from baseline, to baseline) and line width.
Posterize : Produces a special effect in an image by reducing the number of shades of gray or colors to a specified (usually low) number.
PostScript : The page description language created and licensed by Adobe Systems Inc. that is used to display and print fonts and images.
POV : (Point of View) The position and angle used when viewing a scene.
PPI : (Pixels per inch) The unit that is used to measure the resolution of a bitmapped image.

Primary Colors : Colors, usually three, which are combined to produce the full range of other colors within a color model. All non-primary colors are mixtures of two or more primary colors. Red, green, and blue are the primary colors of the additive color model. Cyan, magenta, and yellow are the primary colors of the subtractive color model.
Process Color : Inks that are used to print an image from four separate plates, one each for Cyan (C), Magenta (M), Yellow (Y), and Black (K). In combination, they produce an illusion of an even wider range of colors.
Process Colors : The subtractive primary colors, cyan, magenta, and yellow (CMY), used in process printing.
Purity : The degree to which a color is saturated.